摘要：A topology optimization method based on the solid isotropic material with penalization interpolation scheme is utilized for designing gradient coils for use in magnetic resonance *** the popular stream function method,the proposed method has design variables that are the distribution of conductive material.A voltage-driven transverse gradient coil is proposed to be used as micro-scale magnetic resonance imaging(MRI)gradient coils,thus avoiding introducing a coil-winding pattern and simplifying the coil *** proposed method avoids post-processing errors that occur when the continuous current density is approximated by discrete wires in the stream function *** feasibility and accuracy of the method are verified through designing the z-gradient and y-gradient coils on a cylindrical *** design results show that the proposed method can provide a new coil layout in a compact design space.

摘要：目的:对视网膜映射皮层区V1及V2的视觉调节作用进行初步探讨。方法:利用fMRI方法,对7例健康志愿者采用旋转及扩展棋盘格的视觉刺激进行视网膜皮层映射成像来确定早期视区的位置及大小;然后应用组块设计通过两个不同空间距离的楔形棋盘块进行视觉刺激,将V1及V2皮层区的激活采用ANOVA方法分析比较其变化及意义,以判定不同视区视觉内容的调节方式。结果:上视野对应的V2v区域激活变化显著(P=0.047),并且两个小楔形棋盘块在视野中及映射在皮层表面位置为空间最短距离时激活反应最强烈,激活强度随其中一个楔形棋盘块距离增加而衰减。在V2d区域,有显著调节趋势(P=0.054),在两个楔形棋盘块于同一视野而皮层投影最长距离时反应最弱。初级视皮层V1区域没有发现明显的变化趋势(P=0.073)。结论:视觉内容调节在早期视区主要发生在V2区域,V1区域没有调节功能。如果视觉刺激分别位于左右不同视野内时,V2区域也不发生调节作用。